Electrical connector



C. H. BUCHER ETAL ELECTRICAL CONNECTOR June 28, 1960 3 Sheets-Sheet 1Filed June 20, 1957 INVENTORS (31ml H. liucnlln; GEQRGE J. HANDEI.,JR.

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FIG.8

June 28, 1960 .B CHER T June 28, 1960 FIG.I3

CARI. ll. Bucrmm GEORGE J. HANDEL, JR.

n ed Stat a n ELECTRICAL CONNECTOR Carl H. Bucher, Harrisburg, andGeorge J. Handel, Jr.,

Camp Hill, Pa., assignors to AMP Incorporated, Harrisburg, Pa.

Filed June 20, 1957, Ser. No. 666,920

Claims (Cl. 339-223) This invention relates to electrical connectors andterminals, to crimped electrical connections, and to methods of makingcrimped electrical connections.

It is an object of the invention to provide an improved crimpedconnection between the conducting core of a wire and a connector orterminal. A further object is to form an improved connectionincorporating both an insulation supporting ferrule for a wire and acrimped connection between the conducting strands and the connector. Afurther object is to form a crimped connectlon in which the axis of thewire is in substantial alignment with the axis of the crimped connectionwhich connects the conducting core or strands of the wire and theconnector axis. A further object is to provide a connector which can becrimped onto wires of varying sizes. A further object is to provide acrimped connection by means of which a relatively large cylindricalterminal can be crimpedonto a relatively small diameter wire without theneed of intermediate adapters. A still further object is to provide aconnector having a substantially uniform cross section in its crimpingzone which uniform cross section upon crimping forms both an insulationsupporting ferrule for the wire insulation and a mechanically strong,electrically conductive connection between the strands of the wire andthe connector.

These and other objects of the invention will be apparent from thevfollowing detailed description of the invention and from the annexeddrawings in which:

Figure -l is a plan view of a flat blank formed from sheet metal andfrom which connectors in accordance with the invention are produced;

Figures 2, 3 and 4 show a plan view, a side view, and a perspective viewrespectively of a connector terminal formed from the blank of Figure 1;

Figures 5 and 6 show a side view and a perspective view respectively ofthe connector of Figure 2 as crimped onto the end of a wire;

Figure 7 is a view taken along the lines VI1 -VII of Figure 5;

Figures 8 and 9 are views taken along the lines VIII- VIII and IXIX ofFigure 2;

Figure ,10 is a fragmentary sectional view taken through a die assemblyfor crimping the connector embodiment shown in Figure 2 and showing sucha connector positioned Within the dies for crimping, this view showingthe dies in their open position before crimping; a t Figure 11 is a viewsimilar'to Figure 10 showing th diesin the closed position with acrimped connector positioned between the several cn'mpingdies;

Figure 12 is a view taken along the lines XII-X11 of Figure 10;

Figure 13 is a view similar'to Figure 12 but showing v the dies in thepartially closed position;

Figure 14 is a view taken along the lines XIVXIV of- Figure 11; e

Figure 15. is a view taken alongthe lines XV-XV of Figure 10;

2,943,293 Patented June 2 8, 1960 P we Figure 16 is a view similar toFigure 15 but showing the dies in the partially closed position;

Figure 17 is a view taken along the lines XVII-XVII of Figure 11;

Figure 18 is a sectional view through a plug board and showing thecrimped connector of Figure 6 positioned within the board; and

Figures 19, 20, and 21 are views taken along the lines XIX'--XIX, XX-XX,and XXI--XXI of Figure 18.

. The blank from which the illustrative embodiment of the terminal isproduced comprises a leading end 2 which is subsequently formed into aprojectile-like terminal contact portion and a trailing section 4 whichis subsequently formed into a trough-like section adapted for crimpingonto a wire. This blank is advantageously formed from sheet metal suchas brass or copper by progressive die forming operations and providesparallel edges 6 having semi-circular cut-outs 8 and tapering frontalportions which define a pair of noses 10 on each side of the axis. Acentral nose 12 projects forwardly from between the noses 10 and isconnected by means of a slug or thin strip 14 with the trailing end ofthe next adjacent blank. On each side of the axis of the blankconverging slots 16 are provided and a O-shaped slot 18 is punched outnear the end of the forward portion, the ends of this C-shaped slotbeing in alignment with the axes of the converging slots 16 as shown.

.Notches 19 are provided on the edges of the blank between the leadingend and the trailing end and these notches merge with. the paralleledges 20fof the trailing end. Parallel slots 22a, 22b extendtransversely in the trailing endand between these slots are providedaplurality of depressions 23 which assist in retaining the wire withinthe crimped connection as explained in detail in the copendingapplication of Kemper M. Hammell, Serial No. 604,544, filed August 16,1956. Between the rearward slot 221) and the rear edge .26of the blankare provided a plurality of protrusions 24 in the form of dimples, threesuch dimples being provided in the disclosed embodiment, one beingpositioned on the axisof the blank and one being positioned on each sidethereof. The trailing end or edge 26 of the blank is notched as shown at28 and the previously mentioned connecting slug 14 enters this edgebetween these notches. A pair of relatively narrow notches 25 extendinwardly from edges 20 portion 30.and a trough-like'trailing portion 33.Nose 30provides an outwardly slanted tab 32, which is formed by severingalong a line connecting these slots 16 with the slot 18 and bending thethus severed section of metal outwardly, and also provides a circularopening 31 along its top seam as viewed in Figure 2, formed by thecut-out sections 8 in the blank. It should be mentioned at this pointthat while the invention is particularly disclosed with reference to aconnector having the projectile-like terminal portion on its end, theinvention itself is applicable to alternative types of terminals orconnectors, e.g,,. terminals providing ring-tongue or space ends adaptedto be secured to a stud or the like and to terminals havingspecializedcnd portions of any of the wide variety of available forms.

The trough-like ferrule-forming or crimp-forming portion 33 of theconnector provides sidewalls 34 connected by a base which is identifiedin its rearward portion by 36b and in its section between slots 22a, 22bby 36a.

amazes the rearmost slot 22b. Obliquely directed flanges are formed asshown at 38 extending from the trailing edge of the terminal whichflanges function as stops to prevent insertion of the terminal into aplug board beyond the desired point. These flanges can of course bedispensed where the invention is incorporated into alternative types ofterminals and where the terminal is not adapted to be inserted into aplugboard.

in affixing the uncrimped connection onto a conductor having a strippedend, the conductor is positioned between sidewalls 34 with strippedportions extending between slots 22a, 22b and with unstripped portionsor insulated portions extending rearwardly beyond the rearmost slot 22b.The electrical crimped connection between the connector and the strippedend of the wire is formed by indenting the base portion 36a inwardlyupon itself to form a substantially flat longitudinally extending web 42(Figure 7). This web is indented in most instances to a depth suflicientto provide depending flanges 44 which are bent downwardly as shown at 43from the web, the flanges in turn being reversely bent at 46 to mergewith the sides of the crimp as shown at 17. The marginal edge portionsof the sidewalls are curled towards each other as shown at 48 andreversely curled downwardly towards the floor of the web as Shown at 50.The conducting strands 52 are thus securely locked between the web andthe curled sidewalls of the crimped connection.

The portion of the trough-like part of the connector which liesrearwardly of the rearmost slot 22b is deformed in a somewhat differentmanner than the zone between the slots 22a, 22b, to form an insulationsupporting ferrule for insulated parts of the conductor indicated by C.In the finished connection as shown in Figure 6, the base 36b of theoriginal uncrimped connector may be substantially unchanged from itsoriginal curved shape, but the sidewalls are bent inwardly towards eachother asshown at 54 until their edges are brought into abuttingrelationship. This reformation of this rearward section of thetrough-like cross section reduces its cross sectional area and bringsthe interior surface of this rearward portion into surrounding andconfining relationship with the insulation on the Wire. The protrusionsor dimples 24 assist in confining the insulation as shown in Figure 21in that they are pressed against the surface of the insulation and tendto compress it to hold the wire and take up the tensile stresses whichmight be applied thereto and transmit these stresses directly from theinsulation to the connector rather than from the wire through theelectrical crimp between slots 22a, 22b to the connector. It is ofcourse, advantageous to transmit tensile stresses from a wire throughthe insulation to the connector rather than through the conductingstrands to the connector in order to avoid damage to the electricalcrimp. An additional function of these dimples is to prevent bending ofthe strands on an extremely short radius when the wire is bent at itspoint of entry into the connector. These dimples also prevent severetwisting of the wire strands such as might cause them to work harden andfracture.

it will be apparent that the crimped connection of Fi ure 6 might beformed by a variety of methods and tools however in manufacturing leadshaving terminals on one or both ends it is desirable to perform theoperations in an automatic or a semi-automatic machine providing asingle die set by means of which all of the crimping operations can becarried out upon a single closure of the dies. In Figures 17 there isshown in detail such a die set and the manner in which the terminal iscrimped to produce the completed connection of Figure 6. The dies inthese views are shown fragmentarily and it is understood that thearrangement taught by these views might be used on a simple handoperated press, a semi-automatic press, or a fully automatic press andfeeding means for manufacturing electrical leads as taught for examplein the copending application of Harold A. Kerstetter et al., SerialNumber 562,198, filed January 30, 1956.

In the disclosed tooling for crimping the connector, there is providedan upper die set relatively movable towards a lower die set, and meansfor feeding a terminal between the dies when they are open, so that awire end can be positioned, either manually or automatically, within theterminal and the dies closed to form the completed termination. Theupper die set, as shown in Figure 10, provides an upper crimping die 56for the insulation supporting portion of the connection, an uppercrimping die 58 for the electrical connection between the conductor andthe connector, a hold down 62 for retaining the forward end of theconnector during crimping, a slugout blade 66 for severing theconnecting slugs as the dies are lowered, and suitable spacers 60, 64,for achieving the proper spacing of the dies. The lower die setcomprises an anvil 68 adapted for cooperation with ferrule formingcrimper 56, anvils 70, 72 adapted for cooperation with crimping die 58,a resiliently mounted support 73, and a shearing blade '74 forcooperation with upper shearing blade 66. Anvils 68, 70 and 72 andshearing blade 74 are fixedly mounted in the disclosed embodiment whilesupport 73 is spring biased to the position of Figure 10 but can bedepressed to the position of Figure 11 as explained below. This support73 provides a bearing surface at 75 and a supporting edge at 77 forsupporting the nose portion of the terminal during crimping. A suitablesupport 76 provides a feed track for a succession of terminals, the nextadjacent one of the terminals from one in the die set being shown inFigure 10. 'It is understood that the lower die set and support 76 willordinarily be secured onto the bed or platen of a suitable press and theupper dies will be carried by a tool holder which in turn will becarried by the ram of. the press. The feeding means for feeding theterminals will in many circumstances be coordinated for movement withthe descent of the ram so that an uncrimped terminal is fed between thedies as the ram travels through its cycle, as taught in theaforementioned Kerstetter et al. application.

At the beginning of the crimping cycle, the parts will be shown inFigure 10 with an uncrimped terminal positioned between the open dies.Supporting anvil 70, as shown best in Figure 12, has an upper supportingsurface which provides a ridge 78 bordered on each side by edge portions79 which support the base of the terminal between slots 22a, 22b, whilethe projectile-like frontal portion of the terminal 30 is supported at75 and 77 on resiliently mounted support 73. The dies 68, 72 aresomewhat lower than the die 70 so that the rearward portion of theterminal is supported only in the zone between the slots.

Crimping die 58 which forms the electrical connection between the wirestrands and the connector has inwardly converging sidewalls 80 whichmerge with slightly tapered sidewalls 82. Tapering sidewalls 82, inturn, merge with arcuate surfaces 84 at the top of the die cavity andthese arcuate surfaces curve towards each other to form a central cusp86. As the ram and the die 58 descend, as shown by Figures 12 and 13,the sidewalls 34 of the terminal between notches 19 and 25 are gatheredand flexed towards each other by the side 82 of the die until the edgesof the sidewalls contact arcuate surfaces 84 at the roof of the diecavity. At that point the downward components of the forces acting onthe terminal becomes sufficient to deform the base portion 36a overcentral ridge 78 of die 70 thus forming web 42 and its depending flanges44. As this web is formed, the entire terminal moves downwardly from theposition of Figure 10 to the position of Figure 11 and upon furtherdescent of the ram, upstanding sidewalls 34 between notches 19 and 25are curled by die 58 inwardly towards each other and finally downwardlytowards the internal surface of web 42 to grip tightly the wire strandsand form the electrical connection between the connector and theconductor. It

will be noted that as the terminal moves downwardly from the position ofFigure to the position of Figure 11 as a result of the formation of theweb on its bottom, the portion of the base of the trough-like section isin front of the foremost one of the slots 22a and is lowered onto theupper surface of anvil 72 and resiliently-mounted support 73 movesdownwardly during this interval with the terminal.

During the latter stages of the descent of the ram the insulationsupporting ferrule on the end of the connector is formed by die 56 asshown in Figures 15-17. This die provides gathering portions 90 similarto gathering portions 86 of die 58 and sloping sidewalls 92 which mergeinto a roof section 94 of substantially semi-circular cross section. Thecooperating lower anvil 68 provides a simple arcuate upper surface 88dimensioned to conform to the base of the connector and support itduring the crimping operation. Initially as shown in Figure 10 thisrearmost portion of the connector beyond the rearrnost one of the slots22 is positioned above the surface 88 of die 63. As the connector isindented onits base between slots 22 and as it is lowered relative tothe lower die set, the base at the rear of the connector is brought downonto surface 88 as shown in Figure 16. Thereafter the sidewalls are benttoward each other as they are forced inwardly by tapering sidewalls 92and finally by the semi-circular surface 94 of the die. Thestrengthening or stiffening effect of dimples 24 aids in causing thisportion of the ferrule to assume a segmental cross section, as shown inFigure 17, in the embodiment shown. It is within the purview of theinvention, however, to form an insulation support of circular crosssection if desired. I

Anvil 72 is of substantially the same shape in cross section as anvil 68and supports the frontal portion of the trough-like section of theconnector during the final crimping. During this final crimping it isalso desirable to apply a downward force onthe end of the connector inorder to prevent its being bent in the zone between the crimped sectionand end of the nose. To this end the hold down-device 62 contacts thefrontal portion of the connector as shown in Figure 11 and prevents anysubstantial flexure or permanent bending as a result of reaction to thecrimping forces applied by crimpers 56, 58 Hold down device 62 is ofsubstantially the same shape as crimping die 56 and is not shownspecifically in section. Shearing blade 66 during the initial portion ofthe descent shears slug 14 at the plane between the face of this bladeand block 76. The entire connector then moves downwardly with the slug14 afiixed to its front and this slug is subsequently sheared as shownat Figure 11 as it is forced against the shearing edge of blade 74.

It will be noted that in accordance with the foregoing description, thecrimped connection of the invention is formed by first indenting thebase of the ferrule between slots 22a, 22b, and subsequently curling thesidewalls between the slots to form the electrical connection andbending the sidewalls near the end of the ferrule-forming portion toform the insulation support. It should be understood that this sequenceof the steps is not critical and that the invention can be practiced byfirst curling the sidewalls and then indenting the base. Where theinvention is practiced by the use of a relatively high speed press, theindenting and curling operations will take place within a small fractionof a second and the operation will take place substantiallysimultaneously.

The completed connector of the type shown in the illustrative embodimentis adapted for use in a panel 96 providing a circular opening 98dimensioned to receive the plug which is inserted through the openinguntil tab 32 springs outwardly against the back side of the board tolock the connector into place, the wings or flanges 38 functioning as astop in this connection to prevent insertion of the connector beyond thedesired point. As

shown by the'sectional views 'of Figures 19-21, the cirso that in thisarea the connector does not contact the sidewalls of the opening. Thisarrangement is desirable for the reason that sidewalls of this crimpedarea do not have the same curvature as the walls of opening 98 so thatif the maximum dimension of the crimp itself'were the same as thediameter of the opening it would be difficult to withdraw the plug orpossibly to insert it. The insulation supporting ferrule as shown inFigure 1, however, provides an arcuate base having substantially thesame radius as the radius of opening 98 so that it bears against thesurface of this opening over a substantial area; In addition,the'sidewa'lls, particularly at the apex of their meeting edges, willalso bear against the F opening surface and substantially precludewobbling or movement of the plug within the opening as if this rearportion or insulation supporting ferrule were of circular cross section.

The invention is particularly useful and provides marked advantages whenincorporated into plug-type terminals of the type shown in the drawing.Plugs of this type generally are ofia relatively large diameter relativetothe diameter of the wires withwhich they are used and areadvantageously formed from strip material by progressive die formingoperations. Where the plugs are formed in this manner, the portion ofthe plug which is crimped onto the wire will usually be adapted only toreceive a fairly largediameter wire and in the past recourse has beenhad to an adaptor to accommodate smaller wires in plugs of relativelylarge diameters. It will be apparent that the instant invention obviatesthe need for such an adaptor in that the wire is crimped directly ontothe terminal itself. Another distinct advantage of the invention isthat, as shown in Figure 11, the axis of the wire as crimped in theconnector is in substantial alignment with the axis of the plug itselfand furthermore is in axial alignment with the crimped strands on theends of the wire. In many prior art connectors, where the wire iscrimped in its uninsulated end portion, the axis of the wire will bedisplaced from the axis of the end strands which are crimped to theconnector and this is undesirable in that the strands are bent neartheir ends and thus weakened. The instant invention avoids thisconditionby deforming or crimping the connector from both sides towards itscentral axis to pinch the conducting strands and crimp them to theconnector. A further advantage of the invention is that a range of wiresizes can be accommodated in a single size connector by controlling theextent to which the base of the connector is indented to form web 42 andfurther by controlling the extent to which the sidewalls and their edgesare bent down toward the web. It will be obvious from Figure 7 that ifthe web 42 were somewhat shallower than that shown (i.e., if the flanges43 or 44 were not so high above the surface of the web), a larger wirecould be crimped in the same size terminal. Alternatively, the smallerwire can be adopted by making the flanges even larger and pressing orcurling the sidewalls into closer engagement with the strands andtoward'the web. These latter advantages of the invention inure to usesother than in conjunction with plug type terminals as shown in thedrawing, for example, terminals having ring tongue end portions or spadeend portions.

While we have disclosed a preferred embodiment of our invention and themethod of practicing it, it will be obvious to those skilled in the artthat it is amenable to alternative uses and to alternative arrangementsof the parts.

We claim:

1. The method of crimping onto a conductor having a stripped end theferrule-forming portion of a connector, said ferrule-forming portionhaving a base and a pair of sidewalls extending therefrom, and providinga pair of slots extending transversely across said base and partially onsaid sidewalls, said method comprising the steps of: supporting the baseof said ferrule-forming portion between said slots on an anvil,positioning a conductor within said ferrule-forming portion with itsstripped end extending between said slots and with unstripped portionsextending beyond said slots, displacing said ferrule forming portiontoward and over said anvil to form between said slots a web havingreversely bent flanges extending from the longitudinal edges thereofwhich flanges merge with said sidewalls while simultaneously positioningend portions of said ferrule-forming portion on a second anvil, bendingthe longitudinal edge portions of said sidewalls contained between theplanes of said slots inwardly towards each other and downwardly towardssaid web to form a crimped connection in the zone between the planes ofsaid slots between said stripped end and said ferrule-forming portion,and bending end portions of said sidewalls towards each other to form aninsulation supporting ferrule for said conductor.

2. An electrical connection formed from an initially trough-likeconnector having a base and upstanding sidewalls, said connector beingcrimped into engagement with a conductor to form an electricalconnection with the conducting strands of said conductor and aninsulation supporting ferrule around insulated portions of saidconductor, said electrical connection comprising a web formed by inwarddisplacement of said base and having flanges extending from thelongitudinal edges thereof, said flanges being reversely curled andmerging with said connector sidewalls, said sidewalls being curledtowards each other and into engagement with said conducting strands,said insulation supporting ferrule comprising portions of the base ofsaid connector in substantially undeformed condition and adjacentsidewalls, said adjacent sidewalls being bent towards each other andinto surrounding relationship with insulated portions of said conductor.

3. A connector as set forth in claim 2 wherein said insulationsupporting ferrule provides protrusions on its interior surface incompressing engagement with said insulated portions of said conductor.

4. The method of crimping the ferrule-forming portion of an electricalconnector providing a base having sidewalls extending therefrom onto aconductor, said method comprising the steps of: positioning the strippedend of at least one insulated conductor within said ferruleformingportion with insulation adjacent the end of said conductor disposedwithin the end section of said ferrulefc-rming portion, indenting thebase of said ferrule-forming portion upon itself in the vicinity of saidstripped end to form a web having reversely bent flanges extending fromthe longitudinal edges thereof while substantially simultaneouslybending said sidewalls in the vicinity of said stripped ends towardseach other and towards said web to form a crimped connection betweensaid stripped end and said connector in the vicinity of said strippedend, and bending said sidewalls of the end section of saidferrule-forming portion towards each other to form an insulationsupporting ferrule for said connector.

5. An electrical connector comprising a contact plug portion having anelectrical connection with a conductor and having an insulation supportfor said conductor, said electrical connection and said insulationsupport having been formed from an initially trough-like portion of saidconnector having a base and upstanding sidewalls, said electricalconnection comprising a web formed by inward displacement of said baseand having flanges extending from the longitudinal edges thereof, saidflanges being reversely curled and merging with said sidewalls, saidsidewalls being curled towards each other and into engagement with themetallic core of said conductor, said insulation support comprising thebase of said troughlike portion in substantially undeformed conditionand adjacent sidewalls, said adjacent sidewalls being bent towards eachother and into surrounding and gripping relationship with insulatedportions of said conductor.

References Cited in the file of this patent UNITED STATES PATENTS2,034,090 Douglas Mar. 17, 1936 2,343,522 Bergman Mar. 7, 1944 2,557,126Macy June 19, 1951 2,697,213 Patton Dec. 14, 1954 2,729,695 Pierce Jan.3, 1956 2,783,447 Watts Feb. 26, 1957 2,789,277 Schumacher Apr. 16, 19572,818,632 Hammell Jan. 7, 1958 OTHER REFERENCES ElectricalManufacturing, August 1948, Reprint (AMP) (pp. 1, 2 of 6 pp.).

